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Abstract:

Various exemplary embodiments provide components, devices, and methods of
semiconductor packaging. The disclosed packaging component can include a
mold material disposed around a lead frame and at least an integrated
circuit (IC), wherein the IC is electrically connected with one side of
the lead frame. The opposite side of the lead frame including, for
example, lead segments, can be exposed from the mold material. A variety
of other components, devices, and packages can then be assembled, e.g.,
over the disclosed packaging component, through the exposed regions so as
to improve packaging densities.

Claims:

1. A method for packaging comprising: connecting one or more components
with a lead frame, wherein the one or more components comprise at least
an integrated circuit; and molding a mold material around the integrated
circuit and the lead frame to form a packaging component, such that one
or more lead segments of the lead frame are exposed from the mold
material for a subsequent vertical packaging and one or more external
lead pins of the lead frame extend outside of the mold material for an
external connection.

2. The method of claim 1, further comprising a wire bonding or a
flip-chip mounting for the connection of the one or more components with
the lead frame.

3. The method of claim 1, further comprising packaging one or more
passive components over the packaging component, wherein each passive
component is electrically connected with the integrated circuit (IC)
through the exposed lead segments.

4. The method of claim 1, further comprising packaging a ball grid array
(BGA) structure over the packaging component, wherein the BGA structure
is electrically connected with the integrated circuit (IC) through a
plurality of solder balls and the exposed lead segments.

5. The method of claim 1, further comprising packaging one or more of a
ball grid array (BGA) structure and a second IC chip over the packaging
component; wherein the second IC chip is disposed over the packaging
component; or the BGA structure is electrically connected with the second
IC chip through a first plurality of solder balls and is electrically
connected with the integrated circuit in the packaging component through
a second plurality of solder balls and the exposed lead segments.

6. The method of claim 1, further comprising packaging one or more of a
ball grid array (BGA) structure, a passive component, a second IC chip
and a printed circuit over the packaging component.

7. The method of claim 6, further comprising laminating the printed
circuit over the packaging component; disposing the passive component
over the printed circuit and electrically connecting the passive
component with the printed circuit; disposing the second IC chip over the
printed circuit and electrically connecting the second IC chip with the
printed circuit; connecting the BGA structure with the printed circuit
through a first plurality of solder balls; and connecting the BGA
structure with the integrated circuit in the packaging component through
a second plurality of solder balls and the exposed lead segments.

8. The method of claim 1, further comprising packaging one or more of a
lead frame based packaging component and a passive component over the
mold material, wherein each of the lead frame based packaging component
and the passive component is electrically connected with the integrated
circuit through the exposed lead segments.

Description:

RELATED APPLICATIONS

[0001] This is a divisional of application Ser. No. 12/411,713 filed Mar.
26, 2009 and claims priority from U.S. Provisional Patent Application
Ser. No. 61/105,288, filed Oct. 14, 2008, which is hereby incorporated by
reference in its entirety.

DESCRIPTION OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates generally to the field of
semiconductor device packaging, and more specifically to device packaging
over a mold material.

[0004] 2. Background of the Invention

[0005] A lead frame-based semiconductor device package is the most widely
used integrated circuit (IC) package. The lead frame typically includes a
chip mount pad (also referred to as a die paddle) for attaching the IC
die or chip to the leadframe, and a plurality of lead fingers or
conductive segments (pins) which provide a conductive path between the
chip and external circuits. A gap between the inner end of the lead
fingers and the chip is typically bridged with bond wires attached to
bond pads on the chip and to the inner end of the lead fingers. The outer
ends of the lead fingers remote from the IC chip can be electrically and
mechanically connected to external circuitry.

[0006] The packaged IC may include semiconductor chips and their
associated components, such as passive components or the like embedded
within the mold material. The packaged integrated circuits are connected
or soldered to a printed circuit board (PCB) of an electric device.
Passive components or the like must be placed inside the package so that
they can be located on the lead frame inside the mold material. Through
the printed circuit board, the packaged integrated circuit may be
connected to other chips and to external inputs and outputs.

SUMMARY OF THE INVENTION

[0007] The Applicant has discovered that assembling related components
outside the mold material of a packaged component has advantages over
conventional methods that assemble related components inside the mold
material. In various embodiments, this can be accomplished by exposing or
extending one or more lead frame fingers (also referred to herein as lead
segments) outside the mold material of a lead-frame-based IC packaging
component, such that related components can be packaged over the mold
material rather than inside the mold material.

[0008] In one embodiment, the disclosed IC packaging component can include
one or more IC chips, for example, wire-bonded or flip-chipped, on one
side of the lead frame, while other related components, such as passive
components or the like, can be connected or fixed to the opposite side of
the lead frame. In this manner, a more efficient utilization of the lead
frame can be provided as compared with conventional lead frame based IC
packages, where the IC chips and related components are packaged within
the mold material and on the same side of the lead frame.

[0009] Various related components, such as, for example, passive
components, printed circuit boards (PCBs), ball grid arrays (BGAs), other
ICs, other packaging components, or combinations thereof, can be packaged
in a vertical direction over the IC packaging component through the
exposed regions thereof to provide a high packaging density.

[0010] In various embodiments, the related components, which are directly
or indirectly associated with the IC chips of the packaging component,
can be assembled over the exposed lead frame segments, so as to improve
package densities. In an exemplary embodiment, a second IC chip can be
attached to the top of IC packaging component facing up with a subsequent
BGA package attached thereto. In another exemplary embodiment, a
combination of laminated PCB, BGA, other ICs, and passive components can
be attached on top of the IC packaging component to communicate with the
integrated circuit of the packaging component.

[0011] It is a technical advantage of various embodiments of the invention
that exposing lead segments out from a mold material of a packaging
component provides a high packaging density method for assembling a
variety of components with the IC packaging component.

[0012] The technical advances represented by the invention, as well as the
aspects thereof, will become apparent from the following description of
the preferred embodiments of the invention, when considered in
conjunction with the accompanying drawings and the novel features set
forth in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying drawings, which are incorporated in and constitute
a part of this specification, illustrate embodiments of the invention and
together with the description, serve to explain the principles of the
invention. In the figures:

[0014] FIG. 1 is a schematic cross section depicting a first embodiment of
the invention of semiconductor packaging in accordance with the present
teachings;

[0015] FIG. 2 is a schematic cross section depicting a second embodiment
of the invention using the semiconductor package of FIG. 1 in accordance
with the present teachings;

[0016] FIG. 3 is a schematic cross section depicting a third embodiment of
the invention using the semiconductor package of FIG. 1 in accordance
with the present teachings;

[0017] FIG. 4 is a schematic cross section depicting a forth embodiment of
the invention using the semiconductor package of FIG. 1 in accordance
with the present teachings;

[0018] FIG. 5 is a schematic cross section depicting a fifth embodiment of
the invention using the semiconductor package of FIG. 1 in accordance
with the present teachings; and

[0019] FIG. 6 is a schematic cross section depicting a sixth embodiment of
the invention using the semiconductor package of FIG. 1 in accordance
with the present teachings.

[0020] It should be noted that some details of the FIGS. have been
simplified and are drawn to facilitate understanding of the inventive
embodiments rather than to maintain strict structural accuracy, detail,
and scale.

DESCRIPTION OF THE EMBODIMENTS

[0021] The Applicant has realized that new packaging devices and methods
are needed to improve the packaging density for the IC industry.
Reference will now be made in detail to exemplary embodiments of the
invention, examples of which are illustrated in the accompanying
drawings. Wherever possible, the same reference numbers will be used
throughout the drawings to refer to the same or like parts.

[0022] Various exemplary embodiments provide components, devices, and
methods of semiconductor packaging. The disclosed packaging component can
include a mold material, disposed around a lead frame and at least an
integrated circuit (IC), wherein the IC is electrically connected with
one side of the lead frame. The opposite side of the lead frame
including, for example, lead segments, can be exposed or extended from
the mold material. A variety of other related components, devices, and
packages can then be assembled, e.g., on top of the disclosed packaging
component (rather than within the mold material as known in the prior
art), through the exposed lead segments so as to improve packaging
densities. The lead frame can also include external lead pins extending
outside the mold material for an external connection as known to one of
ordinary skill in the art.

[0023] As used herein, the term "related components" or "other related
components" refers to all possible components or devices that need to be
packaged with the components in the mold material, for example, which can
include at least an IC in the mold material. The "related components" can
include, but are not limited to, passive components, printed circuit
boards (PCBs), ball grid arrays (BGAs), other ICs, other packaging
components, or combinations thereof.

[0024] As used herein, the term "lead segments" or "lead frame segments"
refers to a first set of one or more portions or fingers of the lead
frame, wherein the "lead segments" are exposed or extended from the mold
material and are accessible from a vertical direction for packaging
subsequently with various "related components". In various embodiments,
the exposed "lead segments" can allow the vertically packaged "related
components" and the exemplary IC in the mold material to be packaged on
opposite sides of the lead frame.

[0025] As used herein, the term "vertical direction" refers to a direction
that is about normal to a surface of the mold material. For example,
various related components can be packaged, in a vertical direction that
is on top of the mold material, with the IC located in the mold material.
In various embodiments, the "vertical direction" also refers to a
direction that is about normal to a substrate (e.g., a wafer surface) of
the exemplary IC packaged in the mold material.

[0026] As used herein, the term "lead pins" or "external lead pins" refers
to a second set of one or more portions or fingers of the lead frame,
wherein the "lead pins" are extended outside the mold material for an
external connection, for example, to a printed circuit board (PCB).
Through the PCB, the packaged IC can be connected to, for example,
external inputs and outputs, as known to one of ordinary skill in the
art.

[0027] FIG. 1 is a schematic cross section depicting an exemplary IC
packaging component 100 in accordance with the present teachings. The IC
packaging component 100 can include a mold material 110, an IC 120, a
lead frame 130, and wire bonds 140. It should be readily apparent to one
of ordinary skill in the art that the component 100 depicted in FIG. 1
represents a generalized schematic illustration and that other
components/devices can be added or existing components/devices can be
removed or modified.

[0028] As shown, the IC 120 can be wire bonded to the lead frame 130 by
the wire bonds 140, while the IC 120, a portion of the lead frame 130 and
the wire bonds 140 can be held in position by the mold material 110. Note
that although one integrated circuit IC is shown in FIG. 1, one of
ordinary skill in the art will understand that a plurality of ICs as well
as other related components can be disposed in the mold material 110. In
addition, while the wire bonds are used for connecting IC 120 to the lead
frame 130, various other connections can be used for packaging component
100. For example, the IC 120 can be flip-chip mounted onto the lead frame
130.

[0029] The integrated circuit 120, alone or in combination with other
related components, can include a variety of different features,
including, but not limited to, analog and/or digital circuits such as
digital to analog converters, computer processor units, amplifiers,
digital signal processors, controllers, transistors, or other
semiconductor features. The integrated circuit 120 can include a variety
of materials including silicon, gallium arsenide, or other suitable
materials.

[0030] The integrated circuit 120 can be connected with the lead frame
130, e.g., on one side of the lead frame 130, through the bond wires 140.
In one embodiment, the bond wires 140 can conductively bridge an inner
side of the lead frame 130 with the IC 120, e.g., by attaching to a bond
pad (not shown) on the IC 120. Bond wires can be formed from various
materials, such as gold, copper, aluminum, or other conductive materials
as known to one of ordinary skill in the art.

[0031] The lead frame 130 can have a portion assembled inside the mold
material 110 and can further have a plurality of portions or fingers
including, for example, the lead frame segments 132 exposed from the mold
material 110 for a further packaging process. The lead frame 130 can also
include external lead pins 137 protruded from the mold material 110 for
external electrical connections.

[0032] For example, the lead frame 130 can include one or more lead frame
segments 132 exposing the other side (e.g., opposite to the wire bonded
side) of the lead frame 130 from the mold material 110 to the outside.
Other components including for example, passive components, printed
circuit boards (PCBs), ball grid arrays (BGAs), other ICs or combinations
thereof, which are conventionally packaged in the mold material, can then
be assembled over the exposed side of the lead frame 130 to provide a
high packaging density.

[0033] The lead frame 130 can also include a plurality of external lead
pins 137. The external lead pins 137 can be an extension of the lead
frame 130. In various embodiments, the outer ends of the external lead
pins 137 remote from the IC 120 can be electrically and mechanically
connected to external circuits. For example, the external lead pins 137
can extend outside of the mold material 110 or the packaging component
100 and can be utilized to establish connections between the packaging
component 100 and, for example, a circuit board, when the semiconductor
packaging component 100 is mounted to the circuit board. The lead frame
130 can therefore provide a conductive path between the IC 120 and
external circuits through the lead pins 137.

[0034] During manufacture of the integrated circuit packaging component
100, the IC 120 and other components, if there are any, can be connected
to (e.g., wire bonded or flip-chipped) the lead frame 130. For example,
the IC 120 can be wire bonded to the lead frame 130 using wire bond
connections 140. After assembly of the IC chip 120 to the lead frame 130,
the mold material 110 can be placed around the IC 120, the bonding wires
140, and a portion of the lead frame 130. One suitable molding process
can include an injection molding process. However, other suitable molding
processes including, for example, transfer molding or casting can be
utilized to place mold material around the components. During molding,
the portion of the lead pins 137 can be left extending outside of the
mold material 110 to establish connections with external components.

[0035] In various embodiments, a removable substrate (not shown) can be
used during the packaging process. For example, the IC 120 and/or other
components, and the lead frame 130 can be first placed on the substrate,
e.g., a polyimide-based adhesive or tape. After connecting the IC 120 and
the lead frame 130, the molding process can be conducted to place the
mold material 110 around these components in order to form the packaging
component 100 as shown in FIG. 1. After the molding process, the
substrate can be removed to leave the component 100.

[0036] The mold material 110, which surrounds and holds the integrated
circuit 120, the lead frame 130 and the wire bonds 140 in position, can
include, for example, transfer molding compounds incorporating fused
silica particles or castable compounds.

[0037] In various embodiments, the exposed regions of the packaging
component 100, i.e., the top ends of the exposed lead frame segments 132,
can provide a variety of subsequent packaging platforms for a high device
density. FIGS. 2-6 depict various exemplary embodiments for subsequent
packaging using the package component and method described for FIG. 1 in
accordance with the present teachings.

[0038] FIG. 2 depicts a first example for semiconductor packaging using
the component and method shown in FIG. 1 in accordance with the present
teachings. As shown, the packaged device 200 can include one or more
passive components 220 assembled on top of the packaging component 100.
Passive components and the like are often assembled inside the mold
materials along with IC devices as known in the prior art. By assembling
passive components and/or other related components on top of the
packaging component 100 through the exposed lead frame segments, various
components and/or devices can be packaged vertically, thereby providing
high packaging densities.

[0039] In various embodiments, a plurality of connection contacts can be
used for the disclosed packaging. For example, as shown in FIG. 2, the
connection contacts can include contacts 150 for the IC 120 and for the
exposed lead frame segments 132 and external lead pins 137 to facilitate
related electrical connections. In various embodiments, the connection
contacts can include, e.g., a layer of one or more metals including, but
not limited to, copper, aluminum, gold, silver, nickel, tin, platinum, or
combinations thereof. The connection contacts can include laminated,
plated metal(s) and/or patterned metal layer(s). In various embodiments,
the connection contacts can include one or more circuit traces (not
shown) radiating outward from the packaging component. In one embodiment,
the connection contacts can be a copper pad having a combination of
copper, nickel and gold. In another embodiment, the connection contacts
can be a conduct pad having a combination of nickel, palladium, and gold.

[0040] In various embodiments, the lead frame 130 including the lead frame
segments 132 and the external lead pins 137can be flood-plated with one
or more metals described above, wherein the plated metal(s) can be
present everywhere (not illustrated in the figures) on all the portions
of the lead frame.

[0041] The passive components 220 can include, but are not limited to,
capacitors, inductors, or resistors. The passive component 220 can be
electrically connected with the integrated circuit 120 through the
exposed lead frame segments 132 along with the wire bonds 140 positioned
between the IC 120 and the lead frame 130. Accordingly, the passive
components 220 can include a wire bond termination 225 as shown in FIG.
2. In various embodiments, the passive component 220 can also be
connected with the IC contacts 150 through one wire bond termination 225
so as to communicate with the IC 120.

[0042] FIG. 3 depicts a second example for semiconductor packaging using
the component and method shown in FIG. 1 in accordance with the present
teachings. The packaged device 300 can include an exemplary ball grid
array (BGA) package structure 330 assembled on top of the packaging
component 100.

[0043] For example, the BGA package structure 330 can include a substrate
used as a chip carrier, wherein an IC chip (also referred to as a BGA IC
chip) (not shown) can be arranged on one surface (e.g., top surface) of
the substrate to electrically connect a conductive structure, and a
plurality of solder balls, e.g., the balls 335, can be mounted on the
opposite surface of the substrate to electrically connect the conductive
structure. The solder balls 335 can further be mounted on other electric
components, such as the packaging component 100, through the conductive
structure and the solder balls.

[0044] In the illustrated example, the solder balls 335 can be
electrically connected with, e.g., the exposed lead frame segments 132,
and thus communicate with the IC 120 through bond wires 140. In various
embodiments, as shown in FIG. 3, any BGA structures known to one of
ordinary skill in the art can be packaged on top of the packaging
component 100 to communicate with the IC 120 through the solder balls 335
and the exposed lead frame segments 132. For example, the solder balls
335 can be small eutectic solder balls that are generally about 0.012
inch in diameter and generally formed of a lead/tin alloy as known in the
prior art.

[0045] FIG. 4 depicts a third example for semiconductor packaging using
the component and method shown in FIG. 1 in accordance with the present
teachings. As shown, the packaged device 400 can include a second IC chip
420 and a BGA package 430 vertically packaged on top of the package
component 100 of FIG. 1. In various embodiments, the BGA package 430 can
be similar to the package 330 as shown in FIG. 3.

[0046] The second IC chip 420 can be situated over the packaging component
100, or over the integrated circuit 120. The BGA package 430 can be
assembled, e.g., on top of the second IC chip 420. The BGA package 430
can include solder balls (see for example 435/437) attached or placed on
a substrate surface by soldering the balls to a layer (see for example
432) of, e.g., gold/nickel/copper. The BGA package 430 can be
electrically connected to the second IC chip 420 though the solder balls
435 that are attached to bond pads 425 of the second IC chip 420. The BGA
package 430 can be further electrically connected to the IC 120 through
solder balls 437 connected to the exposed lead segments 132 and the bond
wires 140.

[0047] FIG. 5 depicts a forth example for semiconductor packaging using
the component and method shown in FIG. 1 in accordance with the present
teachings. The packaged device 500 can include, e.g., a printed circuit
510, a second IC 520, a passive component 526 and a BGA structure 530
assembled on top of the packaged component 100 of FIG. 1.

[0048] As shown, the printed circuit 510 can be laminated on top of the
packaged component 100. On top of the printed circuit 510, the passive
component 526 and the second IC 520 can be assembled and electrically
connected with the printed circuit 510. The BGA structure 530 can be
disposed over the passive component 526 and/or the second IC 520. In
addition, the BGA structure 530 can be electrically connected to the IC
120 through solder balls 537 and the exposed lead segments 132. The BGA
structure 530 can also be electrically connected with the second IC chip
520 through solder balls 535. In various embodiments, any suitable
electrical connections between the elements/components can be used for
the packaging devices as disclosed herein.

[0049] FIG. 6 depicts a fifth example for semiconductor packaging using
the component and method shown in FIG. 1 in accordance with the present
teachings. The packaged device 600 can include, e.g., passive components
620 along with a second package structure 650 assembled on top of the
packaging component 100.

[0050] As shown, the passive component 620 can be electrically connected
to the IC 120 through its termination 625. The passive component 620 can
also be electrically connected with the exposed lead segments 132 along
with bond wires 140 to communicate with the IC 120 of the packaging
component 100.

[0051] The second package structure 650 can be, e.g., a second lead frame
based package structure having a plurality of external lead pins 637
electrically connected to an IC chip 620 through bond wires 640. The
external lead pins 637 can be an extension of a lead frame in the package
650 and can be electrically and mechanically connected to the packaging
component 100. For example, the external lead pins 637 can extend outside
of a mold material 610 to establish electrical connections between the IC
chip 620 and the IC 120 through the exposed lead segments 132 and bond
wires 140. In various embodiments, the second package structure 650,
having the second IC chip 620, bond wires 640, and a portion of lead
frame held in the mold material 610, can be similar to the package
component 100. Likewise, a plurality of packaging components 100 can be
assembled vertically through the exposed lead segments 137.

[0052] Notwithstanding that the numerical ranges and parameters setting
forth the broad scope of the invention are approximations, the numerical
values set forth in the specific examples are reported as precisely as
possible. Any numerical value, however, inherently contains certain
errors necessarily resulting from the standard deviation found in their
respective testing measurements. Moreover, all ranges disclosed herein
are to be understood to encompass any and all sub-ranges subsumed
therein. For example, a range of "less than 10" can include any and all
sub-ranges between (and including) the minimum value of zero and the
maximum value of 10, that is, any and all sub-ranges having a minimum
value of equal to or greater than zero and a maximum value of equal to or
less than 10, e.g., 1 to 5. In certain cases, the numerical values as
stated for the parameter can take on negative values. In this case, the
example value of range stated as "less that 10" can assume negative
values, e.g. -1, -2, -3, -10, -20, -30, etc.

[0053] While the invention has been illustrated with respect to one or
more implementations, alterations and/or modifications can be made to the
illustrated examples without departing from the spirit and scope of the
appended claims. In addition, while a particular feature of the invention
may have been disclosed with respect to only one of several
implementations, such feature may be combined with one or more other
features of the other implementations as may be desired and advantageous
for any given or particular function. Furthermore, to the extent that the
terms "including," "includes," "having," "has," "with," or variants
thereof are used in either the detailed description and the claims, such
terms are intended to be inclusive in a manner similar to the term
"comprising." The term "at least one of" is used to mean one or more of
the listed items can be selected.

[0054] Further, in the discussion and claims herein, the term "on" used
with respect to two materials, one "on" the other, means at least some
contact between the materials, while "over" means the materials are in
proximity, but possibly with one or more additional intervening materials
such that contact is possible but not required. Neither "on" nor "over"
implies any directionality as used herein. The term "about" indicates
that the value listed may be somewhat altered, as long as the alteration
does not result in nonconformance of the process or structure to the
illustrated embodiment. Finally, "exemplary" indicates the description is
used as an example, rather than implying that it is an ideal.

[0055] Other embodiments of the invention will be apparent to those
skilled in the art from consideration of the specification and practice
of the invention disclosed herein. It is intended that the specification
and examples be considered as exemplary only, with a true scope and
spirit of the invention being indicated by the following claims.